Use valid log callback for audio modem's audio recorder.

This fixes a crash.

Also change dchecks to checks to catch early. In the unit test we use a mock stream, and there's obviously no (debug built) integration test for this.

BUG=616083
TBR=tommi@chromium.org, xiyuan@chromium.org

Review-Url: https://codereview.chromium.org/2028023002
Cr-Commit-Position: refs/heads/master@{#397127}

components/audio_modem/audio_recorder_impl.cc

@@ -49,6 +49,8 @@ void ProcessSamples(
       content::BrowserThread::UI, FROM_HERE, base::Bind(callback, samples));
 }
 
+void OnLogMessage(const std::string& message) {}
+
 }  // namespace
 
 // Public methods.
@@ -115,7 +117,7 @@ void AudioRecorderImpl::InitializeOnAudioThread() {
                 ? input_stream_for_testing_.get()
                 : media::AudioManager::Get()->MakeAudioInputStream(
                       params, media::AudioDeviceDescription::kDefaultDeviceId,
-                      media::AudioManager::LogCallback());
+                      base::Bind(&OnLogMessage));
 
   if (!stream_ || !stream_->Open()) {
     LOG(ERROR) << "Failed to open an input stream.";

media/audio/mac/audio_auhal_mac.cc

@@ -63,7 +63,7 @@ AUHALStream::AUHALStream(AudioManagerMac* manager,
       log_callback_(log_callback) {
   // We must have a manager.
   DCHECK(manager_);
-  DCHECK(!log_callback_.Equals(AudioManager::LogCallback()));
+  CHECK(!log_callback_.Equals(AudioManager::LogCallback()));
 
   DVLOG(1) << "ctor";
   DVLOG(1) << "device ID: 0x" << std::hex << device;

media/audio/mac/audio_low_latency_input_mac.cc

@@ -270,7 +270,7 @@ AUAudioInputStream::AUAudioInputStream(
       log_callback_(log_callback),
       weak_factory_(this) {
   DCHECK(manager_);
-  DCHECK(!log_callback_.Equals(AudioManager::LogCallback()));
+  CHECK(!log_callback_.Equals(AudioManager::LogCallback()));
 
   // Set up the desired (output) format specified by the client.
   format_.mSampleRate = input_params.sample_rate();